Corn distiller's dried grains with solubles (DDGS) - A value added functional material for wood composites

Corn distiller's dried grains with solubles (DDGS) is widely marketed as a livestock feed due to its high protein content of 34%, fat content of 10%, and low cost of 8-13 cents per kilogram. In recent years, DDGS has been used as a multifunctional filler in synthetic resin bonded wood particleboards to improve their physical and mechanical properties where the adhesive properties of DDGS is derived from its hydrophobic zein proteins. The objective of this research was to evaluate if the high value proteins derived from sodium hydroxide and acetic acid treated DDGS can be functionalized as a natural binder in wood particleboard manufacturing by eliminating the use of harmful formaldehyde resins. Several formulations of particleboard were hot pressed using various concentrations of acid and alkali treatments, DDGS filler contents of 10, 25 and 50 wt.%, and DDGS particle sizes of 120 and 250 mu m. ASTM D1037-12 standard was adapted to evaluate the particleboard properties. Superior flexural strengths of particleboards occurred at press temperature of 190 degrees C. The acetic acid treated particleboards at higher DDGS concentrations exhibited better water resistance properties. Test results showed that the mean internal bond strengths exceeded the minimum requirement of ANSI A208.1-2009. FTIR results showed that the decoupling of proteins was achieved by acid or alkali treatment. These positive outcomes suggest that DDGS has strong potential to act as a natural adhesive for manufacturing medium-density particleboards.